It is known in vehicle seat belt systems to employ a continuous loop of belt having a latch plate assembly slidable along the belt to adjust the relative restraint lengths of the lap and shoulder belt portions. It is also known to provide a retractor mounting one end of the belt, preferably the shoulder belt end, to wind the continuous loop belt to a stored position extending generally vertically between an upper anchor mounting the shoulder belt end on the vehicle body and a lower anchor mounting the lap belt end on the vehicle body. The belt may be unwound from the retractor and extended across the occupant torso to engage the latch plate assembly in a buckle suitably mounted on a vehicle body inboard the occupant seat.
When the latch plate assembly is engaged in the buckle, and a load is imposed on the belt, the belt is clamped to prevent transference of the belt through the latch plate assembly.
It would be desirable to provide a new and improved latch plate assembly which would more effectively clamp the belt when sustained restraint of the seated occupant is needed, and, in particular, to permanently clamp the belt if the load on the seat belt exceeds a predetermined threshold. Accordingly, if the vehicle experiences an incident that requires sustained restraint of the occupant, the belt will remain locked within the latch plate assembly even if the occupant restraining load on the belt is momentarily relieved during the incident.